U.S. patent number 5,604,277 [Application Number 08/391,386] was granted by the patent office on 1997-02-18 for rubber and plastic bonding.
This patent grant is currently assigned to Encore Technologies, Inc.. Invention is credited to John D. Osborn.
United States Patent |
5,604,277 |
Osborn |
February 18, 1997 |
Rubber and plastic bonding
Abstract
A dry liquid concentrate mixture is disclosed comprising crumb
rubber particles and tall oil, tall oil derivatives or other fatty
acids, which may be enhanced by other components, such as
modifiers, for use to enhance the properties of parent materials,
such as thermoplastic compounding and coatings and elastomers and
recycles and asphalt and epoxies and aliphatic urethane.
Inventors: |
Osborn; John D. (Wortham,
TX) |
Assignee: |
Encore Technologies, Inc.
(Houston, TX)
|
Family
ID: |
25388883 |
Appl.
No.: |
08/391,386 |
Filed: |
February 21, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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886338 |
May 20, 1992 |
|
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Current U.S.
Class: |
524/270; 524/274;
524/66; 524/300; 524/322; 521/40.5; 521/43; 521/44; 521/43.5;
521/41; 524/925 |
Current CPC
Class: |
C08L
19/003 (20130101); C08K 5/09 (20130101); C08J
3/226 (20130101); C08K 5/09 (20130101); C08L
19/003 (20130101); C08L 19/003 (20130101); C08L
2666/26 (20130101); C08L 19/003 (20130101); C08L
95/00 (20130101); C08J 2421/00 (20130101); Y10S
524/925 (20130101); C08L 95/00 (20130101); C08L
93/00 (20130101) |
Current International
Class: |
C08K
5/09 (20060101); C08K 5/00 (20060101); C08J
3/22 (20060101); C08J 3/20 (20060101); C08L
19/00 (20060101); C08J 005/10 (); C08J 011/24 ();
C08L 023/00 () |
Field of
Search: |
;524/270,274,300,322,66,925 ;521/40.5,41,43,43.5,44 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Michl; Paul R.
Assistant Examiner: DeWitt; LaVonda R.
Attorney, Agent or Firm: Ostfeld; David M.
Parent Case Text
This is a continuation of application Ser. No. 07/886,338, filed
May 20, 1992, now abandoned.
Claims
What is claimed as invention is:
1. A dry liquid concentrate mixture for use with organic compounds
in nonvulcanized curing systems for plastics, recycled plastics,
thermoplastics, thermoplastic elastomers, polyacrylics,
polyurethanes, urethanes, asphalt, and emulsions thereof, including
latex, comprising a mixture of:
a. crumb rubber including cured and shaped rubber particles;
b. one or more liquid agent consisting of compounds chosen from the
group of fatty acids and tall oil and pitches within the following
ranges of characteristics:
wherein the moisture content of said rubber particles and liquid
agent is not more than 0.5%.
2. The mixture of claim 1 in which the particle size of the cured
rubber particles is finer than about 10 mesh.
3. The mixture of claim 2 in which the cured rubber particles have
a smooth surface.
4. The mixture of claim 2 in which the cured rubber particles have
a rough surface.
5. The mixture of claim 1 wherein there is further included
anti-strip agents.
6. The mixture of claim 1 wherein about a 5 to 30 part per hundred
by weight of liquid agent to cured rubber particles is used.
7. A dry liquid concentrate mixture for use with organic compounds
in nonvulcanized curing systems for plastics, recycled plastics,
thermoplastics, thermoplastic elastomers, polyacrylics,
polyurethanes, urethanes, asphalt, and emulsions thereof, including
latex, comprising a mixture of:
a. crumb rubber including cured and shaped rubber particles;
b. one or more liquid agent taken from the group consisting of
fatty acids and tall oil and pitches within the following ranges of
characteristics:
wherein the moisture content of said rubber particles and liquid
agent is not more than 0.5%, wherein there is further included PVC
plasticizers.
8. An improvement in treating compounds in curing systems,
comprising incorporating into said compounds prior to curing:
a. substantially dry cured and shaped rubber particles;
b. a liquid agent consisting of compounds chosen from the group of
fatty acids and tall oil and pitches within the following ranges of
characteristics:
wherein the moisture content of said rubber particles and liquid
agent is not more than 0.5%.
9. A method of enhancing the cure of a compound selected from the
group consisting of asphalt, plastics, thermoplastic elastomers,
thermoplastics, epoxies, and polyurethanes and urethanes which
comprises adding cured and shaped rubber particles and a liquid
agent consisting of compounds chosen from the group of fatty, acids
and tall oil and pitches within the following ranges of
characteristics:
wherein the moisture content of said rubber particles and liquid
agents is not more than 0.5%.
10. A method for utilizing rubber scrap to yield a final product
with material taken from the group consisting of asphalt,
thermoplastics, thermoplastic elastomers, polyvinyl chloride,
polyacrylates, polyurethanes, urethanes and epoxys, comprising the
steps of:
(1) preparing a dry liquid concentrate mixture by intimately mixing
together cured, shaped rubber particles and a liquid agent
consisting of compounds chosen from the group of fatty acids and
tall oil and pitches within the following ranges of
characteristics:
wherein the moisture content of said rubber particles and liquid
agents is not more than 0.5%;
(2) mixing said dry liquid concentrate mixture with the material to
form a uniform resultant mixture;
(3) treating the resultant mixture with heat energy to yield a
product.
11. The method of claim 10 where step (1) includes mixing said
rubber particles and liquid agent at a temperature above
ambient.
12. The method of claim 11, wherein said temperature is at least
80.degree. C. for said rubber particles and at least 90.degree. C.
for said liquid agent.
13. The method of claim 10, wherein about a 9 to 28 part per
hundred by weight of liquid agent to cured rubber particles is
used, the material is asphalt, and about 17 to 26 part hundred by
weight of dry liquid concentrate mixture to asphalt is used.
14. The method of claim 10, wherein about a 5 to 35 part per
hundred by weight of said liquid agent to cured rubber particles is
used, the material is taken from the group consisting of
thermoplastics and thermoplastic elastomers, and about a 5 to 85
part per hundred by weight of dry liquid concentrate mixture to
thermoplastics and thermoplastic elastomers is used.
15. The method of claim 14, wherein said plastic is a
thermoplastic.
16. The method of claim 14, wherein said resultant mixture is
extruded at a temperature of about 300.degree. F. to 600.degree.
F.
17. The method of claim 16, wherein said temperature range is
between 375.degree. F. to 600.degree. F.
18. The method of claim 17, wherein said thermoplastic is a
thermoplastic coating and the dry liquid concentrate mixture to
thermoplastic coating ratio is about in a range of 10% to 60% by
weight of dry liquid concentrate mixture.
19. The method of claim 17, wherein said thermoplastic are
thermoplastic elastomer and the dry liquid concentrate mixture to
thermoplastic elastomer ratio is about in a range of 5% to 70% by
weight of dry liquid concentrate mixture.
20. The method of claim 17, wherein said thermoplastic is a
recycled thermoplastic and the dry liquid concentrate mixture to
recycled thermoplastic ratio is about in a range of 5% to 70% by
weight of dry liquid concentrate mixture.
21. The method of claim 10, wherein about a 9 to 28 part per
hundred by weight of liquid agent to cured rubber particles is
used, the material is an epoxy, and about a 5 to 40 part per
hundred per weight of dry liquid concentrate mixture to epoxy is
used.
22. The method of claim 10, wherein about a 9 to 28 part per
hundred by weight of liquid agent to cured rubber particles is
used, the material is a polyurethane, and about a 3 to 60 part per
hundred by weight of cured rubber particles to polyurethane is
used.
23. The method of claim 10, wherein step (1) includes mixing the
liquid agent with PVC plasticizers.
24. The method of claim 10, wherein step (1) includes mixing the
liquid agent with anti-strip agents.
Description
BACKGROUND OF THE INVENTION
The invention relates generally to the utilization of scrap tires,
and more particularly to the bonding of rubber and plastic
material.
DESCRIPTION OF THE PRIOR ART
Each year there are an estimated 250,000,000 scrap tires discarded
throughout the united States. Unwanted scrap tire piles, scattered
throughout the country, have been estimated as high as 3 billion
units. The poor biodegradability of scrap tires, their tendency to
trap gases and rise to the surface in landfills, the serious fire
hazard scrap tire piles represent, and the breeding environment
that unwanted scrap tire piles offer to disease carrying pests,
such as rodents and mosquitos, has caused them to be classified as
a serious environmental nuisance.
Attempts to reuse the materials composing scrap tires have had very
limited economic success. Many of these involve destructive
distillation. The approaches to reuse, burn, or distill scrap tires
appear not to have been commercially successful and had little
effect on reducing either the flow or accumulation of scrap tire
carcasses.
Truck tire carcasses with acceptable sidewall structure are
recapped. The original tread stock of a used truck tire is removed
by buffing. The resulting tire buffings, generated from the removal
of the original tread stock, have been the primary feedstock
material for the United States tire generated crumb rubber
industry. This utilization, however, is limited in its scope and
does not address the problem presented by scrap passenger or truck
tire carcasses no longer suitable to be recapped.
Other methods of using scrap tire carcasses have included burning
tire chips for BTU value and low and high vacuum pyrolysis to
recover oil, carbon black, steel and fiber.
Several methods have been employed to enhance the value of scrap
tire derived crumb rubber in vulcanized curing procedures. These
methods are: polymeric coatings to enchanced-manufacture in rubber
goods, addition of various quantities of tall oil derived fatty
acids to adhere rubber particles into a useful mass, sulfur
additions to act as a vulcanizing agent, and various complete
devulcanization processes. Tire generated crumb rubber is also used
in minimal percentages with virgin rubber as a filler and mixed
with hot asphalt as a modifier.
Plastics is a multibillion-dollar industry which produces synthetic
materials and products, many of which were never dreamed of only a
few years ago. Today, civilization requires synthetic materials
(artificial resins produced by chemical reactions of organic
substances). Many products made of plastic produced materials are
produced at less cost than was possible with natural materials.
Plastics, unlike glass or aluminum, are not easily recycled back
into useful products, such as those which they were generated.
Plastics, being a specifically engineered, rather than a generic
material, are sorted prior to recycling. Plastics are seldom
remanufactured back into the product or part which generated them.
Often, recycled plastics are more expensive than new polymers.
Examples of plastics which are recycled include: (1) HDPE and LDPE
into boards, bins, and trash cans and (2) PET into carpet fiber.
The markets for recycled plastics have been slow to develop and do
not appear to be able to keep pace with the generation of new
plastic materials. Once plastics are molded or spun, they lose some
of the characteristics or properties of the virgin material. This
creates a much bigger problem than scrap tires because the United
States generates over 12 billion tons of scrap plastics per year,
most of which is destined for deposit in landfills.
It would be desirable to develop cost feasible, raw material
products generated from a whole scrap tire and plastic feed stocks,
involving the crumb rubber produced from both the sidewall and
tread materials. Because of the vast quantity of accumulated scrap
tires and scrap plastics, it would be beneficial to broaden the
market applications by forming new raw materials containing the
combined properties of both crumb rubber and plastic.
It is well-known in the art to use tall oil with ground rubber
waste for reuse as rubber. See "Ground Rubber Waste--A
Supplementary Raw Material for the Rubber Industry" issued by Kahl
& Co.; U.S. Pat. No. 4,481,335, issued Nov. 6, 1984 to Stark,
Jr. entitled "Rubber Composition and Method"; U.S. Pat. No.
3,873,482, issued Mar. 25, 1975 to Severson et al, entitled
"Pyrolyzed Tall Oil Products as Synthetic Rubber Tackifiers"; U.S.
Pat. No. 4,895,911, issued Jan. 23, 1990 to Mowdood et al, entitled
"Tall Oil Fatty Acid Mixture in Rubber"; U.S. Pat. No. 4,792,589,
issued Dec. 20, 1988 to Colvin et al, entitled "Rubber
Vulcanization Agents of Sulfur and Olefin"; and U.S. Pat. No.
4,224,841, issued Jan. 13, 1981 to Frankland, entitled "Method for
Recycling Rubber and Recycled Rubber Product". Generally for the
area of ground polymer elastomer operation, see U.S. Pat. No.
4,771,110, issued Sep. 13, 1988 to Bouman et al, entitled
"Polymeric Materials Having Controlled Physical Properties and
Purposes for Obtaining These"; and for rubber discussions see U.S.
Pat. No. 3,544,492, issued Dec. 1, 1970, to Taylor et al, entitled
"Sulfur Containing Curing Agents"; and "Organic Chemistry" by
Fieser and Fieser printed 1944 by D.C. Heath & Co. Boston,
pages 346 and 347.
SUMMARY OF THE INVENTION
The present invention is a dry liquid concentrate mixture in
combination with organic and other components which dry liquid
concentrate includes the base combination of: the major constituent
crumb rubber, generated, for example, from processing the tread or
sidewall of scrap tires, and a minor constituent of tall oil, its
derivatives and other fatty acids. This combination forms the dry
liquid concentrate mixture capable of acting as an impact modifier,
homogenizing ingredient, extender, and viscoelastic modifier in a
variety of non vulcanized cure systems for plastics and asphalt.
The dry liquid concentrate mixture can also function as a carrying
agent for additional plasticizing or compatibilizing chemicals to
focus on specific applications.
The preferred dry liquid concentrate is a homogeneous blend of
cured and shaped rubber particles that contain minimum moisture
moisture content and a liquid blend of tall oil, tall oil
derivatives and other fatty acids. These liquid blends plasticize,
swell, and soften the rubber particles, and allow the formation of
chemical bonds between the rubber particle and asphalt,
thermoplastics, thermoplastic elastomers, polyvinylchloride,
polyacrylates, polyurethane coatings and binders, epoxies and other
organic based compounds and is useful in thermoplastic
reclamation.
The dry liquid concentrate mixture imparts elastomeric
characteristics into the parent materials with which it is
combined. Acting as an impact modifier, it helps to improve the
modulus, elongation, and tensile strength, and changes the
viscoelastic characteristics and helps to blend out crystalline
spots in various high molecular weight polymers. Acting as a
processing aid in polyethelylene and other polymeric reclamations,
it homogenizes varieties of various molecular weight polymers
together, imparting beneficial properties that even virgin polymers
do not possess.
The dry liquid concentrate also adds the following captured and
dispersed in the tire rubber: (1) carbon black, (2) ultra violet
stabilizers, (3) heat stabilizers, (4) impact modifiers, and (5)
antioxidants.
DESCRIPTIONS OF THE PREFERRED EMBODIMENT(S)
Cured rubber particles form one of the basic components of a dry
liquid concentrate mixture used in the present invention. The cured
rubber particles used are of natural or synthetic rubber, or the
combination thereof, which has been substantially vulcanized or
cured, as in the manufacture of automobile or truck tires. Truck
and automobile tires constitute the main source of available,
useful cured rubber particles. With respect to tires as a source of
cured rubber particles, the dry liquid concentrate mixture is
equally effective on the rubber generated from either the sidewall
or tread of the scrap tire carcasses. Common rubbers useful for the
dry liquid concentrate of the present invention includes, but are
not limited to: NR, SBR, isoprene, EPDM, neoprene, nitrile, butyl,
and ethylene-propylene diene rubbers. There is no need to separate
the rubbers by polymer content. Crumb rubber produced from the
sidewall or tread. acceptable as a component of the dry liquid
concentrate of the present invention.
The rubber particles should be processed to be substantially free
of contaminants, such as steel and fiber. For best results in
thermally activated reactions, the rubber particles should contain
minimum moisture content, which should be not more than 0.5%
because the water will expand during manufacture.
______________________________________ TIRE GENERATED CRUMB RUBBER
PRODUCT ANALYSIS: (Whole Tire/Tread Stock Only) Product Analysis
Minimum Maximum Method ______________________________________
Acetone Extract 10%/9% 19%/17% BTM-4-07 Ash Content --/-- 8.0%/7.0%
BTM-4-05 Carbon Black Content 28%/27% 39%/38% BTM-4-10 Rubber
Hydrocarbon 42%/45% --/--
______________________________________
Rubber particle shape and size are important elements of the rubber
particles for use with the dry liquid concentrate mixture. The
variety of processing systems designed to recover the available
rubber particles from scrap tire carcasses include: granulation,
stone grinding, cutting, sonic impacting, cracking, and cryogenic
fragmentation. These various processing systems yield particles of
different classes of size and shape. Granulation and cryogenic
fragmentation yield particles with similar height, width, and depth
dimensions, as well as a relatively smooth surface. Stone grinding,
sonic impacting and cracking yield particles with greater surface
area per mesh size and rough surface more conducive to the
formation of mechanical bonds. Rubber particles, regardless of the
method of production, fall into four basic shape categories:
______________________________________ CRYOGENIC MATERIALS: Smooth
Surface ABRADED MATERIALS: Rough Surface TORN MATERIALS: Rough
Surface CUT MATERIALS: Smooth Surface but not as smooth as
Cryogenic Materials ______________________________________
The cured rubber particles maintain their memory of shape in all of
the applications of the dry liquid concentrate mixture. Functional
mesh size is determined by application. Rough surfaces, such as
flake and oblong surfaces, of rubber particles will obtain greater
mechanical bonds and add flexibility to materials in which they are
used. Smooth surfaces, such as cubic rubber particles, are
effective in adding the greatest resistance to abrasion and range
of temperature to materials in which they are used.
Tall oil agent form another of the basic components of the dry
liquid concentrate mixture used in the present invention. Tall oil
agents may be any of Unitol DP-5, commercially available from Union
Camp Corporation, NEO-SPANGOL T20, commercially available from Kahl
& Co. and other formulations consisting of tall oil pitch, tall
oil heads and dimer acid used without sulfur or a sulfur donor.
Tall oil, tall oil derivatives, and other fatty acids which fall
within the following ranges of characteristics may be used in the
dry liquid concentrate mixture:
______________________________________ Viscosity, (centistokes at
99.degree. C.) 10 to 1000 Acid Number, (Total) 15 to 330
Saponification Number 10 to 350 Fatty Acids, % 5% to 100% Rosin
Acids, % 0% to 70% Unsaponifiables 5% to 80%
______________________________________
Mixing of the rubber particles with the tall oil agents is best
accomplished by a dispersion mixing system, such as a ribbon
blender; mastication is not required. Mixing can be done at ambient
temperature, however pre-warming the rubber particles to
approximately 80.degree. C. and introducing of chemical agent
formulations, such as the tall oil formulations, having a
temperature of approximately 90.degree. C. yield the fastest mixing
cycle. Additional processing aids may also be used in the dry
liquid concentrate mixture, such as, for example, pvc plasticizers,
anti-strip agents for asphalt and polyethylene lubricants. These
should be added to the tall oil formulations prior to mixture of
the tall oil with the rubber particles. For best results, the dry
liquid concentrate mixture should be allowed a twenty four hour
standing time prior to usage. The dry liquid concentrate mixture is
hydrophobic and the normal tendency of untreated crumb rubber to
accumulate air-borne moisture is reduced. For most applications a 5
to 35 part per hundred by weight mix rate of the tall oil agent and
other processing aids to the rubber particles is sufficient.
The formulations described above will effect virtually all sizes
and shapes of cured rubber particles. The physical mesh size, shape
and content of the cured rubber particles is determined by
application requirements. For example, in an application of the dry
liquid concentrate mixture with thermoplastics and thermoplastic
elastomers, there are constraints related to extrusion nozzle size,
mold entry ports, and the surface texture required on the end
product. For this purpose, cubic, smooth shaped rubber particles as
additions of equal weight and mesh size have less impact on the
viscosity of blends of the dry liquid concentrate mixture with such
plastics and elastomers than do flake or oblong, rough particles
because the particle has less surface area.
Plastic compounding with a dry liquid mixture can be accomplished
by either a strand extruder or an underwater pelletizer. However
because of low green strength at the extruder nozzle masterbatch,
compounds containing a composition of greater than 25% of treated
crumb rubber are best achieved with the under water pelletizer.
Mixing of the dry liquid concentrate with parent materials other
than thermoplastic, e.g., epoxies, urathanes, asphalt, latex, etc.,
should be done before application to another surface and should be
accomplished by blending a quantity of the dry liquid concentrate
mixture within the viscosity restraints required for the parent
materials usage.
The dry liquid concentrate mixture enhances the snyergisim between
the crumb rubber and the parent material which is not accomplished
without the use of the tall oil, tall oil derivatives, and other
fatty acids. This allows the crumb rubber particles to effectively
impart their physical elastomeric qualities to, for example,
plastics.
Other components which may be included in the dry liquid
concentrate mixture during the application with the parent
materials for various applications (because these components are in
the rubber) are: (1) carbon black, (2) ultra violet stabilizers,
(3) heat stabilizers, (4) impact modifiers, and (5)
antioxidants.
APPLICATIONS:
RUBBERIZED ASPHALT:
The dry liquid concentrate mixture enables the use of crumb rubber
as an asphalt binder modifier without the typical heat blending
reaction cycle. Even dispersion of the dry liquid concentrate
throughout the asphalt mixture is required. In asphalt-rubber hot
mix, the dry liquid concentrate may be added either on the dry
(rock aggregate side) or wet (heated, liquified asphalt) side of
the mix prior to combining. In asphalt emulsions, the dry liquid
concentrate should. be meter blended into the emulsion, in the same
manner as adding to the wet side discussed above.
______________________________________ GRADUATIONS OF REQUIRED
GROUND TIRE RUBBER (HOT MIX ASPHALT) Dense Open Gap Open or Graded
Graded Graded Dense SIEVE SIZE Asphalt Asphalt Asphalt Asphalt %
PASSING TYPE I TYPE II TYPE III TYPE IV
______________________________________ 10 100 100 95-100 100 16 100
75-100 -- -- 30 70-100 25-60 0-10 25-30 50 -- -- 0-2 5-45 80 0-20
0-20 -- -- 100 -- -- -- 0-10 200 0-5 0-5 -- --
______________________________________ DRY LIQUID CONCENTRATE % BY
WEIGHT PER ASPHALT BINDER CONTENT
______________________________________ TYPE I 17%-26% TYPE II
17%-26% TYPE III 17%-26% TYPE IV 17%-26%
______________________________________ CHEMICAL TREATMENT (TALL OIL
FOR EXAMPLE) RATIO BY RUBBER TYPE CHEMICAL TREATING AGENT % BY
WEIGHT OF RUBBER ______________________________________ TYPE I
9%-28% TYPE II 9%-28% TYPE III 9%-28% TYPE IV 9%-28%
______________________________________
In summary, asphalt modification (dry or wet applications) is
accomplished with
a. Rubber particle mesh sizes from less than 10 to greater than 200
depending upon application
b. Dry liquid concentrate % by weight of 9%-28% depending upon
application of asphalt binder
After mixing the dry liquid concentrate made up as set out above
with the asphalt binder, the mixture is added to rock for paving or
is used without rock for crack seal and emulsions, such as for
roofing material.
THERMOPLASTIC:
The preferred method of utilizing the dry liquid concentrate
mixture to modify thermoplastic involves the compounding of the
respective thermoplastic with the dry liquid concentrate mixture.
The preferred extruder is a twin screw system to insure proper
dispersion of the respective thermoplastic with the dry liquid
concentrate mixture. A single screw extruder may also be employed,
however the feed system must be carefully metered to insure proper
dispersion between the thermoplastic and the dry liquid
concentrate. Dry mixing may also be employed, however even
dispersion of the dry liquid concentrate mixture with the
thermoplastic is required to assure part quality. The extruder is
to be operated at the proper melt temperature for the various
thermoplastic relative to the specific melt index of the plastic.
The extruder temperature for most thermoplastic varieties will
range between 300.degree. F. to 600.degree. F., and preferably
375.degree. F. to 600.degree. F.
______________________________________ GRADUATIONS OF REQUIRED
GROUND TIRE RUBBER FOR PLASTICS Coarse Medium Fine Ultra Fine SIEVE
SIZE Rubber Rubber Rubber Rubber % PASSING TYPE I TYPE II TYPE III
TYPE IV ______________________________________ 20 100 -- -- -- 30
80-100 100 -- -- 40 50-80 80-95 90-100 -- 60 0-10 40-65 60-80 -- 80
0-5 0-20 40-65 85-100 100 -- 0-5 15-25 65-90 200 -- -- 0-5 10-25
400 -- -- -- 10-25 ______________________________________ The
fineness of the rubber particles used will depend on the
application.
CHEMICAL TREATMENT (TALL OIL FOR EXAMPLE) RATIO BY RUBBER TYPE
CHEMICAL TREATING AGENT % BY WEIGHT OF RUBBER
______________________________________ TYPE I 9%-28% TYPE II 9%-28%
TYPE III 9%-30% TYPE IV 9%-35%
______________________________________
The percentage of dry liquid concentrate mixture of the CHEMICAL
TREATING AGENT Percentage Table above to thermoplastic is
determined by application (part) requirement.
The chemical formulations of UNITOL DP-5, NEO-SPANGOL T20, and
other formulations derived from tall oil, tall oil derivatives and
other fatty acids are therefore used for mixture with crumb rubber
particles with a moisture content, less than 0.5%, derived
primarily from the processing of scrap tires to yield a dry liquid
concentrate mixture capable of acting as an impact modifier, a
viscoelastic modifier, homogenizing ingredient or an extender
in:
1. Thermoplastic compounding (e.g., PE, PV, PET etc.) with
a. Rubber particle mesh sizes from less than 20 to greater than 400
depending on application
b. Dry liquid concentrate % by weight of 5%-85% depending on
application of thermoplastic compounding
2. Thermoplastic coatings with
a. Rubber particle mesh sizes from less than 80 to greater than 400
(Type III or IV) depending on application
b. Dry liquid concentrate % by weight of 10%-60% depending on
application of thermoplastic coating
3. Thermoplastic elastomers with
a. Rubber particle mesh sizes from less than 20 to greater than 400
depending on application
b. Dry liquid concentrate % by weight of 5%-70% depending on
application of thermoplastic elastomers
4. Thermoplastic recycling with
a. Rubber particle mesh sizes from less than 20 to greater than 400
depending on application
b. Dry liquid concentrate % by weight of 5%-70% depending on
application of recycled thermoplastic
5. Epoxies (grouting, compounding and coatings) with
a. Rubber particle mesh sizes from less than 30 to greater than 200
(Type II, III or IV) depending on application
b. Dry liquid concentrate % by weight of 5%-40% depending on
application of epoxy
6. Coating composition made from an aliphatic urethane with 3%-60%
by weight of treated rubber particles contained in the coating
depending on application of a particle
mesh size ranging from less than 30 no greater than 400 (Type III
or IV).
The admixture of various processing aids for plastics, coatings,
paints, etc. may also be used with rubber particles mixed with such
tall oil, tall oil derivatives or other fatty acids where the dry
liquid concentrate mixture is used as a carrying agent for these
aids, such as PVC plasticizers where the dry liquid concentrate
mixture may be used with a PVC plasticizer before introduction in
the PVC.
In all of these circumstances, the ability is provided to increase
the bonding properties of, for example, cubic rubber (e.g.,
cryogenic), with parent materials, such as plastics.
In thermally driven applications untreated rubber particles swell,
soften, and exchange oils. Because of the high specific heat index
of rubber, this usually requires an extended period of time (20
minutes to 60 minutes at temperatures ranging from 300.degree.
F.-600.degree.F. degrees in asphalt). In Block mold applications
untreated rubber, the cooking time can be as long as 3 to 4 hours
at over 400.degree. F. to cause this action. Additives to the
rubber may be impractical at these temperatures degrading the
performance of the final product, such as a plastic and may render
the process uneconomical because of mold cycle time.
The use of the dry liquid concentrate mixture begins this swelling
and softening reaction without heat. When the dry liquid
concentrate is added to parent materials, the normal heat viscosity
curve, relative to the rubber, has been reduced allowing useful
incorporation into parent materials determined by the parent
materials heat index, thereby overcoming the problems of the prior
art.
EXAMPLES:
ASPHALT:
An AC-20 asphalt may be blended with a 10-30 mesh ambiently
produced crumb rubber (Type I or Type II). The crumb rubber is
blended with 12% (by weight) of Unitol DP-5.TM.. The resulting dry
liquid concentrate mixture is blended into the asphalt at a
temperature of 320.degree. F. The jellified material from this
blending is accomplished within a mix cycle of 5 minutes, instead
of the typical 30 minute cycle and normal reaction temperature of
375.degree. F.
An AC-30 asphalt binder may be mixed with a dense grade aggregate.
The aggregate may be premixed with the dry liquid concentrate at a
rate of 1.1% by weight of the dry liquid concentrate mixture to the
aggregate (which for an aggregate of 92-95% by weight of the final
asphalt binder and aggregate mixture thus yields 9%-28% of the dry
liquid concentrate mixture to the asphalt binder). The crumb
rubber, prior to chemical treatment, would have the following sieve
sizes:
______________________________________ U.S. Standard Sieve %
Retained ______________________________________ 10 -- 30 50-70 50
70-95 100 95-100 ______________________________________
The crumb rubber is blended with 11% (by weight) of Unitol DP-5
.TM..
The resulting lab briquette contained an asphalt binder content of
6%. The briquette showed a 17% softening as a result of the dry
liquid concentrate mixture addition, not known in the art.
THERMOPLASTIC:
I. A whole tire generated ambiently may produce abraded crumb
rubber with the following pre-treatment sieve size:
______________________________________ U.S. Standard Sieve %
Retained ______________________________________ 20 -- 30 20-45 50
70-90 80 95-100 ______________________________________
The crumb rubber may be mixed with 12% (by weight of the rubber) of
NEO-SPANGOL T-20.TM..
The dry liquid concentrate mixture may be dry mixed with recycled
high density polyethylene in a 50%-50% by weight mix and injection
molded in non-compounded form. A 500 ton nitrogen driven injection
mold machine was used in this example. The injection mold machine
was operated at temperature of 450.degree. to 500.degree. F.
The resulting molded part showed even dispersion of crumb rubber
with excellent flow characteristics. Tensile was decreased by 6%,
however, elongation, resistance to abrasion and the cold and hot
temperature properties of the product were each increased by an
average of 50%.
II A recycled HDPE dry liquid concentrate mixture may be prepared
as follows:
______________________________________ Particle Rubber Sieve Size
U.S. Standard Sieve % Retained
______________________________________ 10 -- 30 50-70 50 70-95 100
95-100 ______________________________________
The crumb rubber is mixed with Unitol DP-5.TM. at a weight rate of
12% of the Unitol DP-5 to the crumb rubber. The dry liquid
concentrate mixture is then mixed with recycled HDPE at a rate of
25% dry liquid concentrate mixture to the HDPE and then compounded
through a strand extruder operating at a temperature of range of
450.degree. F.-500.degree. F. The resulting compound may then be
injection molded at a temperature range of 450.degree.
F.-500.degree.F. into a part (such as a pipe thread protector). The
material showed excellent flow characteristics, even rubber
distribution, no loss in tensile strength, increased resistance to
abrasion and increased temperature properties.
III An ambient crumb rubber sample ranging in mesh size from not
less 10 mesh to no greater than 50 mesh may be treated by weight
with 10% Unitol DP-5.TM. to the crumb rubber. The dry liquid
concentrate mixture may then be mixed with polyethylene film. The
mix, by weight, would be 80% dry liquid concentrate mixture and 20%
polyethylene film. The mixture may be placed into a cubic foot
mold. The mold may be closed under five tons of pressure. The mold
may then be placed into an autoclave oven and cooked at 400.degree.
F. for a period of three hours. The resulting block resembler a
solid rubber unit. Core samples could be bent in half without
breaking or tearing. Thus a rubber type material is produced
without the need for sulphur or zinc oxide or accelerators in a
non-vulcanized method while disposing of polyethylene film.
IV An ambient sample of crush rubber ranging from not less then 80
mesh to not more than 200 mesh may be treated with a tall oil
pitch, tall oil heads and dimer acid, such as Unitol DP-5.TM., at a
10% weight ratio to the crumb rubber. The material may be mixed
with thermoplastic copolymers at a ratio of 25% to 40% of dry
liquid concentrate mixture to the thermoplastic copolymers. This
mixture may then be applied with a specially designed flame
thrower, such as manufactured by Plastic Flamecoat Systems, Inc. of
League City, Tex. The resulting coating was applied to both steel
and aluminum and showed excellent properties of adhesion. The
coating was also electrically conductive.
V A cryogenic crumb rubber sample of not less than 60 mesh to not
more than 200 mesh was treated with Unitol DP-5.TM. at a weight of
11% of Unitol DP-5.TM. to the crumb rubber. The dry liquid
concentrate mixture was then compounded with virgin HDPE at a
temperature range from 450.degree. F.-500.degree. F. The compound
mix was 25% dry liquid concentrate mixture and 75% virgin HDPE by
weight.
The rubberized compound was then used at a 25% weight rate with
virgin HDPE and extruded into a 40 mil sheet. The sheet exhibited
no loss of tensile strength, however exhibited greater resistance
to puncture and abrasion than non-rubberized HDPE.
Accordingly, because many varying and different embodiments may be
made with the scope of inventive concept herein taught including
equivalent structures or materials hereafter thought of, and
because many modifications may be made in the embodiments herein
detailed in accordance with the descriptive requirements of the
law, it is to be understood that the details herein are to be
interpreted as illustrative and not in a limiting sense.
* * * * *